Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for supporting a frequency hopping for a low cost user equipment (UE) in a wireless communication system.
Related Art
3rd generation partnership project (3GPP) long-term evolution (LTE) is a technology for enabling high-speed packet communications. Many schemes have been proposed for the LTE objective including those that aim to reduce user and provider costs, improve service quality, and expand and improve coverage and system capacity. The 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of a frequency band, a simple structure, an open interface, and adequate power consumption of a terminal as an upper-level requirement.
In the future versions of the LTE-A, it has been considered to configure low-cost/low-end (or, low-complexity) user equipments (UEs) focusing on the data communication, such as meter reading, water level measurement, use of security camera, vending machine inventory report, etc. For convenience, these UEs may be called machine type communication (MTC) UEs. Since MTC UEs have small amount of transmission data and have occasional uplink data transmission/downlink data reception, it is efficient to reduce the cost and battery consumption of the UE according to a low data rate. Specifically, the cost and battery consumption of the UE may be reduced by decreasing radio frequency (RF)/baseband complexity of the MTC UE significantly by making the operating frequency bandwidth of the MTC UE smaller.
Frequency hopping is a special transmission technique sending data with changing carrier frequency in a certain pattern. 3GPP LTE allows two modes for frequency hopping, enabled by higher layer signaling, from one to the other time slot (intra-subframe) and from one to the other subframes (inter-subframe), or just between subframes. Using hopping enables the UE to exploit the frequency diversity of the wideband channel used in 3GPP LTE while keeping the required contiguous allocation.